The present invention relates to a shape input device which can measure any change in shape of a target object and can input measurement information to, e.g., a measuring instrument.
Conventional shape input devices are disclosed in, e.g., Jpn. Pat. Appln. KOKOKU Publication No. 1-56684 and Jpn. Pat. Appln. KOKAI Publication Nos. 5-113327 and 7-184882. All of these shape input devices have a rod member which can be pivotally set along the joint of, e.g., a wrist or arm, and a detection means which can detect the pivot angle of this rod member. The shape change state of the joint is recognized based on the pivot angle of the rod member which is detected by the detection means when the shape of the joint changes.
A change in joint shape is not a simple shape change component which can be specified by only a change in pivot angle of the rod member. In particular, since motion of the hand or finger is a complicated combination of rotational motion and expanding/contracting motion, it is difficult to obtain the shape change state of the joint of the hand or finger with an angle detection unit having a simple arrangement as described above.
For example, Jpn. Pat. Appln. KOKAI Publication Nos. 5-149706 and 6-3465 disclose a shape input device which can detect the shape change of a hand or finger consisting of a plurality of joints.
The shape input device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 5-149706 has a bend sensor which extends along each finger portion of a flexible glove and the resistance of which changes in accordance with the flexing amount of the corresponding joint of the hand or finger. A change in shape of the hand or finger which is apparently bent the most largely can be detected based on a change in resistance of the bend sensor (this will be called the first prior art).
The shape input device disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-3465 has conductive gel which is applied on each joint portion of a flexible glove and the resistance of which changes in accordance with the flexing amount of the corresponding joint of the hand or finger. A change in shape of the hand or finger can be detected based on a change in resistance of each conductive gel (this will be called the second prior art).
In the above described first and second prior art references, the bend sensor or conductive gel is directly provided on the flexible glove. Accordingly, when a certain joint flexes, this flexing motion is transmitted to another joint portion through the flexible glove to undesirably change the resistance of the bend sensor or conductive gel at this other joint portion. In particular, in the second prior art reference, the influence of the relative translating displacements of the respective conductive gels, which occur upon flexure of the joints, and the influence of strain produced by the flexing displacements of the joints sometimes mix in the detected resistance. As a result, it is sometimes difficult to precisely input a change in shape of the hand or finger. In this case, a change in shape of the hand or finger may be accurately reproduced by signal processing of input data. With this method, however, the lengths of the respective joints of the hand or finger or the link must be measured in advance in units of users, or the input program must be reset in units of users.